• Geomechanics and Engineering
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• v.34 no.1
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• pp.1-15
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• 2023

This study conducts uniaxial compression tests on intact and single crack-contained rocks to investigate the time-frequency domain characteristics of acoustic emission (AE) signals monitored during the deformation failure process. A processing approach, short-time Fourier transform (STFT), is performed to obtain the evolution characteristics of time-frequency domain of AE signals. The AE signal modes at different deformation stages of rocks are different. Five modes of AE signal are observed during the cracking process of rocks. The evolution characteristics of time-frequency domain of AE signals processed by STFT can be utilized to evaluate the damage process of rocks. The difference of time-frequency domain characteristics between intact and cracked rocks is comparatively analyzed. The distribution characteristics of frequency changing from a single band-shaped cluster to multiple band-shaped clusters can be regarded as an early warning information of damage and failure of rocks. Meanwhile, the attenuation of frequency enables the exploration of rock failure trends.

• Clean Technology
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• v.7 no.2
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• pp.133-140
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• 2001

The adsorption characteristics of binary-component Volatile Organic Compounds(VOCs) with benzene and toluene were studied in a fixed bed backed with activated carbon. The adsorption intensites of benzene and toluene resulted from equilibrium adsorption capacity led to roll up phenomenon in a fixed bed and behaved benzene as non-key component which meant the smaller affinity to the activated carbon of the two. From comparion with breakthrough curves between binary-component and single component systems at the same concentration conditions, the stoichiomertic breakthrough time of toluene in both systems had no difference, but that of benzene as non-key component had a tendency to shorten 130min than 200min of single component. In the breakthrough characteristics of binary-component adsorbates, the magnitude of roll-up of the non-key component increased with the increasing of non-key component ratio and aspect ratio(L/D) of fixed bed, while decreased with the increasing of interstitial velocity. Especially, the roll-up phenomenon was more conspicuous with the increasing of mole fraction of key component.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.10
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• pp.5080-5097
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• 2017

Channel characteristics-based secret key generation is an effective physical-layer security method. The issues of how to remove the effect of random noise and to balance the key generation rate (KGR) and the bit mismatch rate (BMR) are needed to be addressed. In this paper, to reduce the effect of random noise and extract more secret bits, a new quantization scheme with high key generation rate and low bit mismatch rate is proposed. In our proposed scheme, we try to use all measurements and correct the differences caused by noise at the boundary regions instead of simply dropping them. We evaluate and discuss the improvements of our proposed scheme. The results show that our proposed scheme achieves lower bit mismatch rate as well as remaining high key generation rate.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09b
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• pp.1271-1273
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• 2005

• Journal of Game and Entertainment
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• v.2 no.1
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• pp.27-34
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• 2006

Computer-assisted animation production tools have an important role in animation production industries. They could reduce the production cost and time, but they rarely copy artistic characteristics of an animators. In this paper, a new computer-assisted line pattern drawing system is proposed. The system automatically copies artistic characteristics of an animator and applies them to computer-generated animations. The artistic characteristics are captured from key frames drawn by an animator. The result shows that the presented approach can copy artistic characteristics from key frames well and reduce time and cost for producing artistic animations.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.7
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• pp.3414-3434
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• 2016

Classical key generation is complicated to update and key distribution generally requires fixed infrastructures. In order to eliminate these restrictions researchers have focused much attention on physical-layer (PHY-layer) based key generation methods. In this paper, we present a PHY-layer fingerprints based fuzzy key generation scheme, which works to prevent primary user emulation (PUE) attacks and spectrum sensing data falsification (SSDF) attacks, with multi-node collaborative defense strategies. We also propose two algorithms, the EA algorithm and the TA algorithm, to defend against eavesdropping attacks and tampering attacks in mobile cognitive radio networks (CRNs). We give security analyses of these algorithms in both the spatial and temporal domains, and prove the upper bound of the entropy loss in theory. We present a simulation result based on a MIMO-OFDM communication system which shows that the channel response characteristics received by legitimates tend to be consistent and phase characteristics are much more robust for key generation in mobile CRNs. In addition, NIST statistical tests show that the generated key in our proposed approach is secure and reliable.

• Journal of the Korean Institute of Landscape Architecture
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• v.34 no.6 s.119
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• pp.87-100
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• 2007

This study analyzed the key words in Korea's leading apartment brands and newspaper advertisements to examine especially their view-oriented advertising characteristics and green marketing properties. Four study topics were established and examined for this purpose. The following are the results; 1. The key words on apartment brands and catch phrases are $\ulcorner$emotion-oriented$\lrcorner$ words, such as taste, pride, and happiness, and $\ulcorner$environment-oriented$\lrcorner$ to appeal to customers with beautiful views of the nature. Also key words on newspaper advertisement headlines stress views for $\ulcorner$environment-oriented$\lrcorner$ characteristics as well as $\ulcorner$emotion-oriented$\lrcorner$ characteristics for elegance and luxury, and $\ulcorner$function-oriented$\lrcorner$ characteristics for the future. Views, nature and park are key words and everything about illustration that are especially emphasized even on the headlines of newspaper advertisements. 2. Unlike brands or headlines, sub-headlines and body copies stress $\ulcorner$modern-oriented$\lrcorner$ characteristics for life, culture, and accessibility, followed by $\ulcorner$emotion-oriented$\lrcorner$ characteristics. Key words on caption were also highly $\ulcorner$modern-oriented$\lrcorner$, followed by $\ulcorner$environment-oriented$\lrcorner$ and $\ulcorner$function-oriented$\lrcorner$ characteristics for practical aspects. 3. In result of $X^2-test$, $\ulcorner$environment-oriented$\lrcorner$ key words that convey good views, naturalism, parks, and nature are the major representation of green marketing strategies of apartment brands and newspaper advertisements. However, brands were strongly $\ulcorner$emotion-oriented$\lrcorner$, whereas captions were $\ulcorner$modern-oriented$\lrcorner$ and body copies were $\ulcorner$investment-oriented$\lrcorner$. Both apartment brands and advertisements were consistently $\ulcorner$environment-oriented$\lrcorner$, but were not consistent in other factors. 4. Different parts of newspaper advertisements are focusing on green marketing strategies in terms of environmental protection, but are actually leaning toward modern-oriented lifestyles and accessibility. Thus, it is more well-being marketing rather than green marketing. To pursue true green marketing despite the limits of newspaper advertisements, it is necessary to present products and pricing strategies that represent sustainable.

• Ocean Systems Engineering
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• v.3 no.3
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• pp.167-180
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• 2013

Hydrodynamic characteristics of a bluff cylinder oscillating along transverse direction in steady flow were experimentally investigated at Reynolds number of $2{\times}10^5$. The effects of non-dimensional frequency, oscillating amplitude and Reynolds number on drag force, lift force and phase angle are studied. Vortex shedding mechanics is applied to explain the experimental results. The results show that explicit similarities exist for hydrodynamic characteristics of an oscillating cylinder in high and low Reynolds number within subcritical regime. Consequently, it is reasonable to utilize the test data at low Reynolds number to predict vortex induced vibration of risers in real sea state when the Reynolds numbers are in the same regime.

• Membrane and Water Treatment
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• v.1 no.1
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• pp.83-92
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• 2010

To improve the antifouling characteristics of polypropylene hollow fiber microporous membranes in a submerged membrane-bioreactor for wastewater treatment, the surface-modification was conducted by Ar plasma treatment. Surface hydrophilicity was assessed by water contact angle measurements. The advancing and receding water contact angles reduced after the surface modification, and hysteresis between the advancing and receding water contact angles was enlarged after Ar plasma treatment due to the increased surface roughness after surface plasma treatment. After continuous operation in a submerged membrane-bioreactor for about 55 h, the flux recovery after water cleaning and the flux ratio after fouling were improved by 20.0 and 143.0%, while the reduction of flux was reduced by 28.6% for the surface modified membrane after 1 min Ar plasma treatment, compared to those of the unmodified membrane. Morphological observations showed that the mean membrane pore size after Ar plasma treatment reduced as a result of the deposition of the etched species; after it was used in the submerged membrane-bioreactor, the further decline of the mean membrane pore size was caused by the deposition of foulants. X-ray photoelectron spectroscopy and infrared spectroscopy confirmed that proteins and polysaccharide-like substances were the main foulants in the precipitate.

• The Plant Pathology Journal
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• v.37 no.5
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• pp.437-445
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• 2021

Tilletia laevis Kuhn (syn. Tilletia foetida (Wallr.) Liro.) causes wheat common bunt, which is one of the most devastating plant diseases in the world. Common bunt can result in a reduction of 80% or even a total loss of wheat production. In this study, the characteristics of T. laevis infection in compatible wheat plants were defined based on the combination of scanning electron microscopy, transmission electron microscopy and laser scanning confocal microscopy. We found T. laevis could lead to the abnormal growth of wheat tissues and cells, such as leakage of chloroplasts, deformities, disordered arrangements of mesophyll cells and also thickening of the cell wall of mesophyll cells in leaf tissue. What's more, T. laevis teliospores were found in the roots, stems, flag leaves, and glumes of infected wheat plants instead of just in the ovaries, as previously reported. The abnormal characteristics caused by T. laevis may be used for early detection of this pathogen instead of molecular markers in addition to providing theoretical insights into T. laevis and wheat interactions for breeding of common bunt resistance.